title: Differential effect of autoinducer 2 of Fusobacterium nucleatum on oral streptococci.
abstract: Autoinducer 2 (AI-2) is a quorum sensing molecule and plays an important role in dental biofilm formation, mediating interspecies communication and virulence expression of oral bacteria. Fusobacterium nucleatum connects early colonizing commensals and late colonizing periodontopathogens. F. nucleatum AI-2 and quorum sensing inhibitors (QSIs) can manipulate dental biofilm formation. In this study, we evaluated the effect of F. nucleatum AI-2 and QSIs on biofilm formation of Streptococcus gordonii and Streptococcus oralis, which are initial colonizers in dental biofilm. F. nucleatum AI-2 significantly enhanced biofilm growth of S. gordonii and attachment of F. nucleatum to preformed S. gordonii biofilms. By contrast, F. nucleatum AI-2 reduced biofilm growth of S. oralis and attachment of F. nucleatum to preformed S. oralis biofilms. The QSIs, (5Z)-4-bromo-5-(bromomethylene)-2(5H)-furanone and d-ribose, reversed the stimulatory and inhibitory effects of AI-2 on S. gordonii and S. oralis, respectively. In addition, co-culture using a two-compartment system showed that secreted molecules of F. nucleatum had the same effect on biofilm growth of the streptococci as AI-2. Our results demonstrate that early colonizing bacteria can influence the accretion of F. nucleatum, a secondary colonizer, which ultimately influences the binding of periodontopathogens.
authors.affiliation: Department of Oral Microbiology and Immunology, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
authors.forename: Yun-Ji
authors.initials: YJ
authors.lastname: Jang
authors.forename: Jaehyun
authors.initials: J
authors.lastname: Sim
authors.forename: Hye-Kyoung
authors.initials: HK
authors.lastname: Jun
authors.forename: Bong-Kyu
authors.initials: BK
authors.lastname: Choi
mesh_terms: D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D018920:Coculture Techniques; D016967:Fusobacterium nucleatum; D006714:Homoserine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors; D006801:Humans; D007783:Lactones / Q000008:administration & dosage* / Q000037:antagonists & inhibitors; D053038:Quorum Sensing / Q000187:drug effects / Q000502:physiology*; D012266:Ribose / Q000494:pharmacology; D012463:Saliva / Q000382:microbiology*; D013053:Spectrophotometry; D054773:Streptococcus gordonii / Q000187:drug effects* / Q000254:growth & development; D019533:Streptococcus oralis / Q000187:drug effects* / Q000254:growth & development
chemical_list: D007783:Lactones; C091088:N-octanoylhomoserine lactone; D012266:Ribose; D006714:Homoserine
keywords: Autoinducer 2; Biofilm; F. nucleatum; Oral streptococci; Quorum sensing inhibitors